Mounting for carriers for coils of flexible strip material in taping and other material



July 26, 1932. A. B. F. G. RICHARDSON 1,358,915

MOUNTING FOR CARRIERS" FOR COILS OF FLEXIBLE STRIP MATERIAL IN TAPING AND OTHER MATERIAL Filed Feb. 15, 1931 I I l INVENTDR Y I mmaim ATTORNEYS Patented July 26, 1932 UNITED STATES PATENT OFFICE ARTHUR BRUCE FRASER GILLESPIE RICHARDSON, OF BELVEDERE, ENGLAND MOUNTING FOR CARRIERS FOR OOILSOF FLEXIBLE STRIP MATERIAL IN TAPING AND 7 OTHER MATERIAL Application filed February 13, 1931, Serial No. 515,573, and in Great Britain February 19, 1930.

This invention relates to the mounting of a carrier for a coil of flexible strip material which is to be drawn off under tension while the carrier travels in a circular path. These conditions occur, for instance, in the machines in which strips of insulating material, for instance paper, are applied to a conductor in the manufacture of an electric cable. In carriers working under such conditions it is desirable to control the tension on the strip and methods fordoing this have been worked out in which a friction brake is applied to a rotary part of the carrier, the loading of the brake being due to aspring pressure of tension exerted in a direction parallel with the axis of the carrier. An example of such tension controlling device is set out in the specification ofthe application for a patent, Serial No. 453,891 filed 20th May, 1930, now Patent No. 1,849,883, March 15, 1932. We have found that in some cases of this kind the desired value of braking force is not obtained and investigation shows that the efiect is dependent upon the general arrangement of the mounting in the machine. Where the carriers are mounted in such a way that the axis about which the coil turns as the strip is drawn oil, is in such a direction that the centrifugal force action on the carrier, due to its travelling in a circular path, has an important component along or parallel with the axis of the coil, this component force may influence the braking effect and may even be considerably greater than the force applied by the spring and may act in the same or in the opposite direction. Accordingly such an arrangement is liable to be defective to a degree dependent upon the precise disposition of the parts of the mounting and the speed at which the carriers revolve. The present invention has for its object to remove this source of irregularity.

The invention consists in combining with the mounting and the braking device operated by spring pressure or tension in a direction parallel with the axis of the mounting device, an anti-friction thrust bearing supporting the resultant of this axially directed spring force and the component, in a direction parallel with the axis of the mounting device, of the centrifugal force exerted on the coil and its drawing and will now be described, by way of example, as completely asis necessary for the purpose of enabling the present invention to be fully understood.

The accompanying drawing shows a sectional elevation of an arrangement to control the tension in flexible material being withdrawn from two coils such as is described in the specification of the application for a patent, Serial N 0. 453,891 iiled 20th May, 1930, but which has been modified by the provision of anti-friction thrust bearings designed, notonly to restrain the coil carriers from moving axially along the carrier spindle under the action of the springs by which the axial braking forces are produced, but also to restrain the carriers from movement under the action ofthe component forces, in directions parallel with the coil axes, of the centrifugal forces exerted upon the coils and their holders when the arrangement is being revolved about the main axis of the taping machine.

In the accompanying drawing,

Figure 1 is a side elevation, partly in section, showing the part of the device nearest the taping machine on which it is intended to be used; and

Figure 2 is a continuation of Figure 1.

Referring now to the drawing, the coils 2 and 3 of strip material are carried upon their respective coil holders or carriers 4 and 35 which in turn are mounted in a rotatable manner upon the carrier spindle 1, the latter being secured at one end by the nut 5 to the member 6 attached to the rotating head of the taping machine. As shown in the drawing, the axis of the carrier spindle 1 is more nearly radial to than parallel with the main axis of the taping machine and hence, the components in a direction parallel with the carrier the carrier spindle 1.

spindle axis of the centrifugal forces acting upon the coils and their carriers will be of considerable magnitude. The centrifugal forces acting upon the coils and their carriers will not be constant but will depend upon the speed of the taping machine and upon the size of the coilswhich latter will vary continually as the material is withdrawn from them.

The coil carrier 1 consists of an outer tubular part 7-, on the outside of which the coil of material 2 is mounted and secured by being gripped between the collar 8 and the flange 9; of an inner tubular part 10 which works on the spindle and serves as a bearing for the carrier; and of a radially extending web 11 uniting the two parts 7' and .10. The annular recess 12 thus provided to the left of the web 11 houses a part of the coil spring 13 by means of which the axially applied braking force is produced. This compressed spring 13 exerts pressure upon the web 11 and upon the rotating discs 14 of the friction braking device 15, the axial position of the latter being controlled, with the aid of the rod 36 passing through the spindle 1, by the nut 33 which works on the screwed end of the spindle and is driven by the right hand coil holder 35 through gearing 34.

In the arrangement shown, the component in a direction parallel to the shaft 1 of the centrifugal force exerted on the coil 2 and the carrier 1, when the apparatus is revolving about the main axis of the taping machine, will tend to move the carrier 1 away from the inner end, that is to say, the left hand end, of Such movement would, if permitted, allow the spring 13 to elongate and would reduce the brakin force exerted upon the holder 4 from that which would be exerted by the spring 13 were the taping machine at rest. This would result in the braking force being reduced as the machine gathered speed and then, after constant speed had been reached, in the braking force being gradually increased as the size of the coil diminished. If the movement of the carrier 4 to the right were resisted by a collar located upon the spindle and against which the web ll'were permitted to bear, variation in spring force due to the action of centrifugal forces would be prevented but a small bralring force, increasing from a zero value to a maximum as the machine gained speed, additional to the desired braking force produced by the action of the spring 13, would result from the friction between the web 11 and the collar. To avoid these two undesirable effects an anti-friction bearing, in the form of a ball-thrust washer 16, is located to the right of the carrier 1. To facilitate the withdrawal from and replacement upon th carrier spindle of the coil carriers, the right hand coil carrier is carried upon a sleeve 17, this sleeve being so arranged that normally other by a radially extending web 21.

(i. e. when the arrangement is completely assembled ready for working) it cannot rotate or axially move with respect to the carrier spindle 1. The ball thrust washer 16 is conveniently carried upon this sleeve 17 and is axially positioned thereon, by split rings 18 and 19, so that web 11 bears upon the left hand face of tne washer 16. By this arrangement, movement of the carrier 4 due to the action of centrifugal force is prevented Without a corresponding braking force of considerable magnitude being produced; any variation in pressure between the web 11 and th washer 16 due to a variation in centrifugal force will only produce a corresponding frictional braking effect which is negligible compared with that produced by the device 15.

The right hand coil carrier 35 is of somewhat similar construction to that of the carrier 41, having an outer tubular part and an inner tubular part 20 which are united to each The annular recess houses a part of the coil spring 23 by means of which the axially applied braking force is produced. The compressed spring 23 exerts pressure upon the web 21 and upon the rotating discs 24 of the friction breaking device 25, the axial position of which is controlled by the means controlling that of the braking device 15. The coil carrier 35, however, difi'ers from the carrier 1 by having its outer tubular part constructed of two parts, 26 and 27, fitting one upon the other and maintained in correct relationship by screws 28. The carrier is so constructed in order that a ball-thrust washer 29 may be partly housed within the circumferential groove 30 formed between the web 21 and an inwardly ext-ending flange 31 on the part 26. The thrust washer 29 is located upon sleeve 17. in a similar manner to that in which the washer 16 is located, being positioned by the split rings 19 and 32. By this means any appreciable movement axially along the shaft of the carrier 35 is prevented.

The action of centrifugal force upon the coil 3 and its carrier 35 will tend to move the latter axially alon the sleeve 17 and to the rightthat is, away from the supported end of the carrier spindle land so tend to compress the spring 23 and increase the braking efiect produced by the device 25. The possibility of such movement however, is prevented by the flange 31 contacting with the left hand face'of the thrust washer.

Whether the thrust washer 29 is in contact with the flange 31 and the split ring 32 or in contact with the web 21 and the split ring 16 will depend upon whether the axial component of the centrifugal force exerted upon the carrier 35 and its coil 3 is greater or less than the axial force exerted by the spring 23. In the drawing it is assumed that the apparatus is revolving about the main axis of the taping machine and that the component of the centrifugal force exerted upon the coil 3 and its carrier 35 is greater than the force exerted by spring 23. However it does not materially affect the working of the apparatus since the amount of movement permitted the carrier is limited to the difference between the thickness of the thrust washer 29 and the distance between the adjacent faces of the web 21 and flange 31; the difierence being usually of the order of a few thousandths of an inch, the change in spring force is negligible.

It was pointed out that the frictional loss caused at the thrust washer 16, though small, was increased by the action of the centrifugal force on the carrier 4 and its coil 2. The corresponding loss at the washer 29 will at first be reduced by the centrifugal force acting on the carrier 35 and its coil 3, the frictional loss being, in this case, produced by a force which is equal to the difference between the pressure exerted by the spring 23 upon the carrier and the axial component of the centrifugal force acting upon the coil 2 and carrier 35. The loss may, in fact, become zero at certain speeds of the taping machine. Beyond the speed at which the axial component of the centrifugal force becomes equal to the spring force any further increase in speed will usually result in an increase of friction at the washer 29.

The above described means, whereby the influence of centrifugal force upon a preferred form of tension controlling mechanism can be substantially eliminated, has been described for the purpose of illustration only. Our invention may be applied to any form of coil mounting device which is subj ected to the action of centrifugal forces due to the travel of the carrier in a circular path; it is not essential that the braking force should be applied in the way described. Whilst the component, in a direction parallel to the carrier spindle, of the centrifugal force acting on the coils and carriers has been described as being in a direction away from the point of support of the spindle, the above is the case only if the unsupported end of the spindle is further from the main axis of the machine than is the supported end.

\Vhat I claim as my invention and desire to secure by Letters Patent is 1. An arrangement for controlling by a braking device the tension on flexible material being withdrawn from a coil mounted on a spindle which itself revolves in space about an external axis, which comprises the spindle, a coil carrier rotatably mounted thereon, a friction braking device also mounted on the spindle and controlling the freedom of relative movement of said carrier and spindle, a spring bearing against the carrier and applying pressure to the brak ing device, an anti-friction thrust washer mounted on and fixed in position axially relative to the spindle and a surface on the car rier in contact with that face of the washer for pressing these parts together in a direction parallel with the spindle axis, and means comprising an anti-friction thrust bearing action between the carrier and the spindle and supporting the resultant of the reaction of this axial compression and the component, in a direction parallel to the spindle axis, of the centrifugal force exerted on the coil and its carrier and restraining the carrier from appreciable axial movement under the influence of such resultant force.

In testimony whereof I aflix my signature.

ARTHUR BRUCE FRASER GILLESPIE RICHARDSON. 

